Tub mandrel

ABSTRACT

A PAPER TUB IS FORMED ON A ROTATING MANDREL BY WINDING TWO SECTIONS OF PAPER ONTO THE MANDREL, ONE OVER THE OTHER. THE SECTIONS OF PAPER ARE HELD TO THE MANDREL BY A VACUUM WHICH IS APPLIED TO THE PAPER SECTIONS THROUGH ORIFICES IN THE MANDREL. AFTER THE PAPER IS WRAPPED AROUND THE MANDREL AND GLUED TOGETHER, PRESSURED AIR IS SENT THROUGH SOME OF THE AIR LINES TO THE ORIFICES IN THE MANDREL. THE PRESSURE AIR FORCES THE TUB OFF THE MANDREL TO ANOTHER POSITION.

Sept. 20, 1971 Q BUHLE 3,605,513

TUB MANDREL Filed July 14, 1969 2 Sheets-Sheet 1 INVENTOR RUSSEL C. BUHLE BY 4 Z e m ATT'Y.

Sept. 20, 1971 c, BUHLE 3,505,573

7 TUB MANDREL Filed July 14, 1969 2 Sheets-Sheet 2 AUX. VACUUM SUPPLY BL OF R UPP VACUUM PICKUP IN VEN TOR RUSSEL C. BUHLE BY 4 v ATT X 3,605,573 TUB MANDREL Russell C. Buhle, Clarendon Hills, Ill., assignor to Continental Can Company, Inc., New York, N.Y. Filed July 14, 1969, Ser. No. 841,332 Int. Cl. B31c 7/06, 11/04; B31b 1/06 US. Cl. 9339.3 7 Claims ABSTRACT OF DISCLOSURE My invention relates to a tub forming machine and particularly to the mandrel of the tub forming machine and its means for holding the segments of paper onto the mandrel and then blowing the formed tub off the mandrel.

In the prior art, cup bodies are made by wrapping a single sheet of paper around a mandrel, holding the sheet to the mandrel by either mechanical or pneumatic means, and continuing to hold the sheet to the mandrel, being particularly careful that the sheet is held to the mandrel along the seam line. After the glue sets at the seam, the cup is forced off the mandrel by means of an air jet or a mechanical actuator.

Small containers made of a single thickness of paper are sufiieiently sturdy to stand normal usage. However, large containers need a heavier wall if they are to be used in normal trafiic. A solution to this problem is to use two layers of paper in the container wall rather than one layer. The apparatus of the present invention Winds two separate wrapping segments about a mandrel to form the wall of a large container with at least two thicknesses of paper.

It is an object of my invention to hold a double layer of paper to the mandrel.

It is another object of my invention to force a tub from the mandrel after the tub has been formed.

It is a further object of my invention to form the tub and force it from the mandrel without damaging the tub.

It is a final object of my invention to provide a means for winding a double layer of paper onto a mandrel for forming a tub and holding the double layer on the mandrel until the glue has set.

In brief, my invention is to a mandrel having a plurality of orifices along the rounded surface of the mandrel. Some of these orifices are connected to a vacuum source and the rest are connected at times to a vacuum source and at other times to a source of pressurized air. Two sections of paper are wrapped about the mandrel, and each section is glued to the other to form a tub body. The bottom is crimped into place to form the complete tub, and the tub is then forced off the mandrel by a blast of pressurized air to the second set of holes in the mandrel.

The above and other objects will become apparent from the following description and drawings in which:

FIG. 1 is a schematic diagram of a tub-making machine;

FIG. 2 is a view taken partly in cross-section of the mandrel of my invention;

FIG. 3 is a view taken in cross-section of FIG. 2.

The inner wrap feed hopper 1 (FIG. 1) is loaded with curved paper wrapping segments 2. Underneath the pile of curved wrapping segments is the inner wrap platen 3. This platen moves forward and backward and as it moves United States Patent ice forward toward the mandrel, it carries with it the lowermost of the wrapping segments 4. The platen has a gulley or slot located in the platen on the side toward the air jet. The air jet shown to the right in the drawing directs a jet of air against the edges of the lowermost wrapping segments and separated the lowermost of the wrapping segments so that there is a clear separation between the bottom two or three wrapping segments. The lowermost segment is then drawn down into the gulley 5 and passes by the air jet 6 toward the nip roller 7. All other segments press against the front caliper bar 8 which stops their motion. Posts 9-12 hold the segments in place. The single bottom segment 4 passes under the caliper bar 8 and the motion of the lower platen 3 is just extensive enough to allow the lead edge of the lowest wrapping segment to be caught by the nip rollers 7. From this point forward, the turning of the nip roller moves the wrapping segment. The nip roller pulls the segment from its lowest position in the pile and passes it along toward the area of the glue pot 14 and the glue applicator roller 15. The glue applicator puts a thin layer of glue onto the outer or bottom surface of the inner wrap as the inner wrap is conveyed by it. The mandrel 16 is rotating and the lead edge of the segment hits the mandrel and is pulled onto the mandrel by the vacuum in the mandrel holes 17. As the mandrel rotates, its rotation wraps the segment 4 around the mandrel. Finally, the railing edge of the inner wrap is fed to the mandrel. After some of the mandrel has been covered by the inner wrap, the other half of the machine sets into operation. The outer wrap platen 18 moves the lowermost 19 of the outer wrap segments forward. The outer wrap segments differ from the inner wrap segments in that they are usually stenciled or printed in some way to decorate the outer shell of the tub. This segment 19 goes through almost exactly the same series of operations as was described above in reference to the inner wrap segment. Most of the outer Wrap segment is wrapped about the inner wrap segment on the mandrel 16, and the two have glue applied to their bottom surface. The glue holds them together. The outer wrap is initially laid down with its leading edge about behind the leading edge of the inner wrap. Since the outer surface of the inner wrap has an adhesive coating and the outer wrap 19 may have an adhesive coating on its bottom or inner side, the outer wrap is fastened to the inner wrap when the adhesive coating dries. The last few inches of the outer wrap is coated on its inside with a thin adhesive coating. This last few inches is pressed against the outer side of the outside wrap below it. In the finished tub, the inner plies 4 and outer plies 19 of the tub are fastened to each other along their extent. Now, the blow-off air source is connected to the blow-01f air orifices and the tub is ejected from the mandrel onto the next operation.

The tub body is a frustrum of a cone and each of the plies is a developed section of this cone. When the blow off air is applied to the formed tub, the air forms a lubricating surface between the tub and the mandrel as well as applying force to the tub body to eject it from the mandrel.

While the inner and outer wraps are being wound about the rotating mandrel 1'6, vacuum is applied through the vacuum pick-up supply 20 and the auxiliary vacuum supply 21. All of the air holes 17 apply vacuum to the inner wrap. The operation of the valves 22, 23 controlling the vacuum supply or the air supply 24 is accomplished by earns 25, 26 which are ganged to rotate simultaneously. The inner wrap and the outer wrap have had an opportunity to glue together, and the seams of the inner wrap and outer wrap are now fastened together, i.e., the tub walls are fastened together.

Shortly thereafter, the vacuum supplies 20, 21 (FIG. 2) are switched off and the blow-off air supply 24 is applied through the blow-oif air holes 17 and the annular groove 117. At this time, the tub body 35 leaves the mandrel and is ready for further manufacturing operations.

The operation of the tub forming mandrel is seen most readily in FIGS. 2 and 3. The mandrel itself rotates at a constant speed in one direction. Around the outer surface of the mandrel are a number of orifices 17, 28. Some of these orifices are connected directly to a vacuum source 20. In the conduit 27 between the vacuum source and the orifice is a valve 23. The valve is turned off and on by rotating cam 26.

The other group of orifices 17 are connected by conduit 29 to a three-way valve 22 which connects this group of orifices either to an auxiliary vacuum supply 21 or to a blow off air supply 24. This valve is likewise controlled by a rotary cam 33. The two rotary cams 25, 2 6 are ganged so that their operation is synchronized to bring about the effects discussed above in regard to the forming and blow-off of the tub.

Considering the cam actuating the on-otf vacuum pickup supply valve 23, when the valve contact or control element 29 is riding the high dwell 30 vacuum is applied to the mandrel; when the valve contact element is riding the low dwell 31 the vacuum is shut off and no vacuum is applied to the mandrel.

The cam 25 of the two-Way valve operates in the high dwell 32 to connect the orifices 28 to the blow oif air and in the low dwell 33 position, the valve connects the orifices to the auxiliary vacuum. The cams rotate synchronously with the rotating mandrel. However, they are geared so that each cam turns a complete revolution during the forming of a tub.

The vacuum sources 20, 21 are connected to the mandrel while the tub body is being formed. The mandrel may rotate at any desired speed so long as the operation of forming the tub is finished when the blow-off air supply 24 is connected through the conduit to a certain number of orifices 17 in the mandrel surface.

By having a large number of orifices connected to one or more vacuum supplies, a high degree of vacuum is applied to the tub walls. By this means, the tub Walls are held to the mandrel. Without a large number of orifices and a fairly high degree of vacuum applied to the exterior of the mandrel, skewing and size control are difiicult to achieve and maintain. Also, slippage of the inner ply in the mandrel would be possible. As shown in FIG. 3, there are, in the present embodiment, five lines of orifices about the rotating mandrel. The lower set of orifices 28 are connected to the vacuum supply 20 only. The other four sets of orifices 17 are connected to the auxiliary vacuum supply 21 or to the blow-off air supply 24 depending on the phase in the tub body forming cycle.

Although the embodiment shown here in FIG. 3 has one series of vacuum pick-up orifices, and four series of blowolf air and auxiliary vacuum orifices, it is readily appreciated that these orifices can be of any number and dispersed about the rotating mandrel in any desired positions depending upon the characteristics of the tub body to be formed.

This machine, operated as described in the preceding paragraphs, makes a tub of two layers of materials.

The advantages of the machine are that two blanks are wrapped one about the other to form a tub body, the complete operation is done on one machine, a high degree of vacuum is applied to the inner surface of the tub blanks, a significant savings of material is effected by the use of two segmented body blanks rather than one continuous strip out from a sheet of material, and the tub body is ejected from the mandrel by blow-oif air after the tub is formed.

The foregoing is a description of an illustraive embodiment of the invention, and it is applicants intention in the appended claims to cover all forms which fall within the scope of the invention.

I claim:

1. A tub body forming mandrel system comprising:

a mandrel mounted on a fixture for rotation about the longitudinal axis of the mandrel;

said mandrel having a flattened end and a rounded lateral surface;

orifices in said rounded surface;

first passageways in said mandrel for connecting some of said orifices to a first passageway in said fixture;

second passageways in said mandrel for connecting others of said orifices to a second passageway in said fixture;

a first vacuum source;

conduit means connecting said first vacuum source to said first passageways in said fixture;

first on-otf valve means in said conduit means for connecting and disconnecting said orifices and said first vacuum source;

a second vacuum source;

:an air pressure source;

a second valve having three orifices and having a switch for connecting a first one of said orifices with one and then the other of said two other orifices located in said valve;

conduit means connecting said first orifice of said second valve to said second passageway of said fixture;

conduit means connecting one of said other orifices in said second valve to said second vacuum source; and

conduit means connecting the second of said other orifices in said second valve to said air pressure source.

2. A tub body forming a mandrel system as set forth in claim 1 further comprising:

a first moving cam for selectively opening and closing said first valve means to connect and disconnect said vacuum source from said first passageways; and

a second moving cam for selectively moving said 'valve switch to connect said first one of said orifices to said pressure source and to said second vacuum source at different times during the rotation of the mandrel; and

means for connecting said moving cams to each other for simultaneous movement whereby the vacuum sources are applied to some of said mandrel orifices simultaneously and after the tub is formed, the air pressure source is applied to some mandrel orifices.

3. A tub body forming mandrel system as set forth in claim 2 in which:

said second moving cam connects said second vacuum source to said series of orifices at the same time that said first moving cam connects said first vacuum source to said other orifices.

4. A tub body forming mandrel system as set forth in claim 3 comprising:

stacking means for a pile of curved wrapping segments mounted to each side of said mandrel;

a platen forming the bottom of said stacking means for moving the bottom segment of said segment pile toward said mandrel;

nip rolls for moving said segment toward said mandrel;

and

glue applicator roll means for coating the underside of said Wrapping segments whereby when said seg ment is wrapped onto said mandrel and held to the mandrel by the mandrel vacuum, the overlapping portion of the segment adheres.

5. A tub body forming mandrel system as set forth in claim 4- in which:

a first stacking means for holding a stack of first wrapping segments, nip rolls and glue applicator are located to one side of said mandrel whereby said first segment is fed onto the bottom of said mandrel; and

a second stacking means for holding a stack of second References Cited wrapping segments, nip roll, and glue applicator are located to the other side of said mandrel from said UNITED STATES PATENTS first stacking means whereby said second segment is 1,756,243 4/1930 Benson 93 39'3 is fed onto the top of said mandrel and attached to 5 1555941 4/1932 Bodony 93-94(Fc) the first segment to form the side wall of a tub. 2,415,625 2/1947 cqker 93-94(FC) 6. A t-ub body forming mandrel system as set forth in 2,666,542 1/1954 Pnce 9394(Fc) claim 5 in which: 1 2,748,830 6/1956 Nash 9377(CL) said first segment is applied to said mandrel at the same 3,049,979 8/1962 Sayford 93 39-3 time that said vacuum means are connected to said 10 310951156 6/1963 Wamken 93-79X mandrel. 3,399,516 9/1968 Hough 93-77(CL) 7. A tub body forming mandrel system as set forth in 3,425,325 2/1969 Lynch 93-79 claim 2 in which:

an annular orifice is formed in said fixture and connect- WAYNE S JR., Primary Examiner ed to said second passageway for allowing blow-off 15 US CL XR' air to escape and impel said tub body from said mandreL 93-77CL, 79, 941 0 

